Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Food Science Technology

An efficient microwave irradiation pretreatment (MIP) method was applied to maintain high content and high quality essential oils (EO) of dry rosemary leaves and dry fennel fruits. Different times and levels of MIP were employed, the findings indicated that the oil yield increased as MIP power increased. Where, the highest yield of rosemary and fennel essential oil was obtained at 180 and 90 watts for 1 and 5 minutes, respectively, with an increment rate 14.91 and 17.14 %, respectively. In general, our data showed that although there are common increasing trend of yield of rosemary and fennel essential oils with increasing microwave irradiation power and time, the relationship was not linear. The obtained essential oils were fractionated and identified by using GC/MS technique.The main constituents of rosemary essential oil extracted by hydrodistillation only were 1,8 cineol, Ü-pinene and camphor, however, MIP increased the amounts of Ü-pinene, Ý-pinene, camphor and Ü-terpineol. Generally, MIPof rosemary oil led to disappearance of 1-octen-3-ol and limonene, simultaneously estragole, which was not present in control oil

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